BULB SHELL FOR LED LIGHT BULBS
A bulb shell includes a transparent shell base having an opening, a largest outer diameter and a light projection surface defined by a critical boundary on the shell base, and a coating on the shell base in a region between the opening and the critical boundary to increase brightness of the light projection surface. The critical boundary lies between a first position where the largest outer diameter is located and a second position distant from the first position by 33% of the dimension of the largest outer diameter in a direction away from the opening. The coating will significantly increase the brightness of the light projection surface when the bulb shell is used in a LED light bulb.
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The present invention is related to a bulb shell for light-emitting diode (LED) light bulbs.
BACKGROUND OF THE INVENTIONConventionally, in order to increase the brightness of a light projection surface of a LED light bulb, the LED light bulb is designed to use more LEDs or high power LED. However, either solution consumes more power and causes higher operating temperature of the LED. To maintain good performance of a LED, the operating temperature of the LED must be controlled within an appropriate range. Using more LEDs or high power LED will increase the operating temperature of the LED light bulb and thereby increase the cost of the heat sink required for maintaining the operating temperature of the LED light bulb. As a result, the total cost of the LED light bulb is increased.
SUMMARY OF THE INVENTIONAn object of the present invention is to provide a bulb shell for LED light bulbs to enhance the brightness of the light projection surface of the LED light bulbs.
According to the present invention, a bulb shell for LED light bulbs includes a transparent shell base having an opening, a largest outer diameter and a light projection surface defined by a critical boundary on the shell base, and a coating on the shell base in a region between the opening and the critical boundary to increase brightness of the light projection surface. The critical boundary lies between a first position where the largest outer diameter is located and a second position distant from the first position by 33% of the dimension of the largest outer diameter in a direction away from the opening.
In a LED light bulb having a bulb shell according to the present invention, the coating will reflect light emitted by the LED device of the LED light bulb and thus converge the light of the LED light bulb within a conical angle established by the LED device and the critical boundary. As a result, the brightness of the light projection surface may be increased up to more than twice, without increasing the cost and power consumption of the LED light bulb.
These and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which:
The brightness of the light projection surface 16 is affected by the location of the critical boundary 20. For instance, referring to
Referring to
While the present invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and scope thereof as set forth in the appended claims.
Claims
1. A bulb shell for LED light bulbs, comprising:
- a transparent shell base having an opening, a largest outer diameter and a light projection surface defined by a critical boundary on the shell base; and
- a coating on the shell base in a region between the opening and the critical boundary to increase brightness of the light projection surface;
- wherein the critical boundary lies between a first position where the largest outer diameter is located and a second position distant from the first position by 33% of the dimension of the largest outer diameter in a direction away from the opening.
2. The bulb shell of claim 1, wherein the critical boundary is at a position distant from the first position by 4% of the dimension of the largest outer diameter in the direction away from the opening.
3. The bulb shell of claim 1, wherein the critical boundary is at a position distant from the first position by 5% of the dimension of the largest outer diameter in the direction away from the opening.
4. The bulb shell of claim 1, wherein the critical boundary is at a position distant from the first position by 27% of the dimension of the largest outer diameter in the direction away from the opening.
5. The bulb shell of claim 1, wherein the shell base has a rough surface.
6. The bulb shell of claim 1, wherein the shell base is made of glass or plastic.
7. The bulb shell of claim 1, wherein the coating is on a portion of an inner surface of the shell base.
8. The bulb shell of claim 1, wherein the coating comprises a reflective film.
9. The bulb shell of claim 8, wherein the reflective film comprises a metal.
10. The bulb shell of claim 9, wherein the metal comprises aluminum.
Type: Application
Filed: Oct 19, 2010
Publication Date: Jul 21, 2011
Applicant: LIGHTING DEVICE TECHNOLOGIES CORP. (HSINCHU CITY)
Inventors: CHIEN-HOUNG LIU (TAIPEI CITY), YUNG-MING TSAO (KAOHSIUNG CITY), YING-CHIEH TSAI (TAICHUNG CITY)
Application Number: 12/907,367
International Classification: H01J 19/54 (20060101);